Stir in a bowl 1 stick melted butter, add 3 tablespoons Piri Piri sauce. Add 1 lb. peeled and uncooked shrimp, toss to coat. Place in a large baking dish in a single layer. Pour any remaining butter mixture over the shrimp. Heat at 375 degrees until shrimp are pink and curled, about 10 minutes. Drizzle with 2 tablespoons fresh lemon juice. Sprinkle with parsley. Season and serve hot.